Strain-induced magnetization in collinear antiferromagnet RuO2

RuO2 is a colinear antiferromagnet with many interesting properties, including spin current generation arising from its band topology, crystal Hall effect, spin-valley locking and piezomagnetism, and Néel vector-dependent spin current generation from its band anisotropy. While the piezomagnetism, which originates in strain-lifting of the valley degeneracy, has been theoretically predicted, experimental realization has remained elusive. We find an emergent net magnetization in strained RuO2 on Al2O3 and on TiO2 and propose to investigate the origins using polarized neutron reflectometry.

RuO2是一种共线反铁磁体（colinear antiferromagnet），具有诸多有趣特性，包括由能带拓扑产生的自旋电流、晶体霍尔效应、自旋-谷锁定、压磁效应（piezomagnetism），以及由能带各向异性导致的奈尔矢量（Néel vector）依赖型自旋电流产生。尽管源于谷简并度应变解除的压磁效应已获理论预测，但其实验实现仍未可知。我们在Al2O3和TiO2衬底上的应变RuO2中发现了涌现净磁化，并提议采用极化中子反射法（polarized neutron reflectometry）探究其起源。